Since its inception in 1956 a major focus of the Seattle Longitudinal Study has been on understanding changes in cognitive abilities as one ages and how factors, such as lifestyle, health, and personality, influence cognitive functioning. Now understanding changes in the brain with age and ther leationship between neural functioning and behavior is an important compliment to cognitive studies. In 2005 we added a neuroimaging component to our study, facilitated by the return of Drs. Schaie and Willis to Seattle and affiliation with the University of Washington. Fortuitously, a new Integrated Brain Imaging Center (IBIC) was created at the UW about the time our neuroimaging work began and has enhanced our efforts.
Three types of neuroimaging procedures are included in our research: structural MRI (studying brain volume), diffusion tensor imaging (studying white matter integrity), and functional fMRI (studying activity in the brain when at rest or involved in a task). Our imaging research is conducted at the South Lake Union UW campus. GIven the expense and time required in neuroimaging, only a subset of SLS members have participated and were selected from those that have been in the SLS during both midlife and old age.
Findings remain at an early stage. Our early work has focused on identifying brain areas associated with cognitive abilities studies in the SLS. Read on for a summary of findings from one of our publications.
Midlife memory predicts brain volume in old age
Most research in aging has focused on normal versus pathological aging but little research has focused on optimal aging. The SLS has found that some individuals during midlife appear to improve or decline on the cognitive measure of episodic memory (memory for time-related events and experiences). We sought to determine if memory performance in midlife memory predicts hippocampus volumes in non-demented adults in middle and old age.
Eighty four SLS participants whose episodic memories had improved, declined or remained stable during midlife were selected for structural MRIs to equally represent two birth cohorts: Midlife and Old Age. We analyzed MRIs by comparing three measures of brain volume 1) hippocampus 2) total brain and 3) hippocampus to total brain ratio. Analyses revealed: 1) Hippocampus volume was greater for the Midlife cohort; Midlifers had 6% greater total brain volume than the Old Age cohort; 2) Those in Old Age with improving memory change had greater hippocampus volume than those with stable or declining memory within the same cohort; Old Age memory improvers had a greater hippocampus to total brain ratio than those with stable or declining memories in Old Age.
Results showed that midlife memory change predicts hippocampus volume in Old Age. Although Old Age improvers have relatively equal hippocampus volume to those in Midlife, total brain volume for Old Age is less than total brain volume for Midlife. Episodic memory scores in Midlife did not predict hippocampus volume. This study illustrates the significance of midlife memory change on future memory funcion and hippocampus volume. It is the first study to examine the impact of midlife memory improvement on cognitive and brain aging. Implications of this suggest that early interventions in midlife can improve brain health in old age.
For the complete article visit, Borghesani, P. R., Weaver, K. E., Aylward, E. H., RIchards, A. L., Madhyastha, T. M., Kahn, A. R., Liang, O., Ellengbogen, R. L., Beg, M. F., Schaie, K. W., & Willis, S. L. (2012). Midlife memory improvement predicts preservation of hippocampal volume in old age. Neurobiology of Aging, 33, 1148-1155 (PMC30740212).